The present invention is directed to integrated circuits. More particularly, the invention provides an adaptive multi-level threshold system and method for over-current protection. Merely by way of example, the invention has been applied to a power converter. But it would be recognized that the invention has a much broader range of applicability.
Power converters are widely used for consumer electronics such as portable devices. The power converters can convert electric power from one form to another form. As an example, the electric power is transformed from alternate current (AC) to direct current (DC), from DC to AC, from AC to AC, or from DC to DC. Additionally, the power converters can convert the electric power from one voltage level to another voltage level.
The power converters include linear converters and switch-mode converters. The switch-mode converters often use pulse-width-modulated (PWM) or pulse-frequency-modulated mechanisms. These mechanisms are usually implemented with a switch-mode controller including various protection components. These components can provide over-voltage protection, over-temperature protection, and over-current protection (OCP). These protections can often prevent the power converters from suffering permanent damage.
For example, a conventional OCP uses a single threshold level, which can limit the current on a cycle-by-cycle or pulse-by-pulse basis. But this conventional technique usually cannot adequate protect the power converters under certain operating conditions.
Hence it is highly desirable to improve techniques for over-current protection.